In a recent study, researchers tested different types of antibiotics as a potential endometriosis treatment.
Endometriosis is a chronic condition that can lead to pelvic and lower abdominal pain and infertility. About 10% of women between 25 and 40 years old have endometriosis. This condition can cause a significant reduction in quality of life. Endometriosis treatment involves surgery and hormone therapy, but these treatments do not prevent endometriosis from coming back.
Bacteria in the reproductive tract may be associated with endometriosis
One theory explaining the cause of endometriosis is bacteria. The bacterial community in the reproductive tract of women with and without endometriosis has been extensively studied. Some types of bacterial communities are associated with reproductive disorders.
Researchers at the Department of Obstetrics and Gynecology at the Washington University School of Medicine conducted a study on mice to test the theory that the bacterial community in the gut may influence endometriosis disease progression. The results of this study were published in Human Reproduction.
The researchers used a well-established endometriosis model in mice. A day after inducing endometriosis in mice, the researchers gave the mice drinking water containing a mixture of four different antibiotics, vancomycin, neomycin, metronidazole, and ampicillin. They added aspartame to the drinking water to mask the taste of the antibiotics. These mice treated with antibiotics were compared with mice who were given drinking water with only aspartame. After three weeks consuming the antibiotic-containing drinking water, the mice were killed, and samples were collected from the gut and reproductive tract.
The group of mice with endometriosis that consumed the drinking water with antibiotics had smaller lesions in their reproductive tract compared with mice receiving drinking water with just aspartame.
In another experiment, the researchers gave the mice drinking water with antibiotics first and then performed the endometriosis induction surgery. In this case, the mice treated with antibiotics before the induction had smaller lesions than the aspartame-only group.
These two experiments suggest that antibiotic treatment can reduce the progression of endometriosis and reduce the early growth of endometriotic lesions.
The researchers also analyzed the gut bacterial community in the mice treated with antibiotics. Higher bacterial diversity was found in the gut of mice with endometriosis that did not receive antibiotics. The lowest amount of bacterial diversity was found in the mice treated with antibiotics.
Metronidazole may be more effective for endometriosis
The researchers further examined the effects of metronidazole and neomycin alone as an endometriosis treatment. Mice treated with metronidazole had smaller lesions than the mice treated with neomycin. Metronidazole-treated mice also had fewer inflammatory factors present in the lesions.
Finally, metronidazole-treated mice with endometriosis were fed feces from mice with endometriosis. Endometriotic lesions formed and were similar in mass and volume as those from endometriosis mice that were given aspartame drinking water. This suggests that the bacterial community in the gut can influence the development and progression of endometriosis.
Further studies are required to determine whether these effects also occur in humans. If gut bacteria can influence the development and progression of endometriosis in humans, this has the potential to result in a new endometriosis treatment.
Written by Jessica Caporuscio, PharmD
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Reference: Chadchan SB, Cheng M, Parnell LA, et al. Antibiotic therapy with metronidazole reduces endometriosis disease progression in mice: a potential role for gut microbiota. Hum Reprod. 2019.